I am running a twitter poll on how many web apps people have saved to their iPhone: http://twtpoll.com/r/g3bnth
I have a pretty techy following and this just doesn't seem to be done with any regularity. Maybe half of the people have saved at least one web app, but how many native apps have they installed.
I think this tells us two things:
1) saving a web app doesn't really make it any better than just using that web app in mobile safari.
2) apple has little incentive to prioritize the testing and developing of this feature since so few people actually use it.
Seems like a non-issue to me.